SDSS LRGs: 0.001 of the observable volume of the Universe (Loeb &Wyithe 2008)

What is the best time to be a cosmologist? At early time, Hubble scale grows, but due to expansion the comoving distance starts to shrink: objects enter and exit the horizon. The optimal cosmic epoch for precision cosmology was at z = 10 (http://arxiv.org/abs/1203.2622)